There is a virtually endless list of applications for devices that can provide stimuli to and/or receive output from and/or detect states of any number of systems, including living beings, machines, chemicals, etc. For example, conductors can deliver energy to systems, such as delivering electricity to a muscle to stimulate contraction of the muscle. Also, conductors can be used to sense electric impulses produced internally to a body to determine when or whether the body has instructed the muscle to contract. Optical fibers can deliver light to systems, e.g., to cause a reaction that can be detected by optical fibers, or other means such as electrical conductors. Beside electrochemical devices, optical fibers and optical fiber bundles allowing simultaneous sensing and imaging have been used increasingly for a variety of different applications.
As technology advances, there is a push toward smaller, faster, more quickly responsive actuators and sensors. Microelectrodes provide small voltage-drop devices for transferring energy, be it for providing stimuli or measuring electrical output. Microelectrodes are gaining increased importance in electrochemical analysis and sensor technology as their small size leads to small faradaic currents, reduced iR drop and steady-state diffusion currents.